Digital communication receivers typically must sample an incoming waveform and then reliably detect the sampled data. Signals traveling through a dispersive medium typically suffer from group delay and attenuation. The group delay creates pulse spreading, inter-symbol interference and other noise. In order to compensate for such channel distortions, communication receivers often employ well-known filtering, amplification and equalization techniques. For example, zero equalization or decision-feedback equalization (DFE) techniques (or both) are often employed. Such equalization techniques are widely-used for removing intersymbol interference and to improve the noise margin. See, for example, R. Gitlin et al., Digital Communication Principles, (Plenum Press, 1992) and E. A. Lee and D. G. Messerschmitt, Digital Communications, (Kluwer Academic Press, 1988), each incorporated by reference herein.
Communication receivers also often amplify a received signal with a small form factor pluggable (SFP) limiting amplifier. When the dispersive signal passes through the SFP limiting amplifier, however, the output of SFP limiting amplifier exhibits pulse width shrinkage resulting in loss of jitter tolerance. A need therefore exists for methods and apparatus for improving the jitter tolerance in an SFP limit amplified signal.